• Title, Summary, Keyword: Ion energy distribution

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Monitoring Ion Energy Distribution in Capacitively Coupled Plasmas Using Non-invasive Radio-Frequency Voltage Measurements

  • Choi, Myung-Sun;Lee, Seok-Hwan;Jang, Yunchang;Ryu, Sangwon;Kim, Gon-Ho
    • Applied Science and Convergence Technology
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    • v.23 no.6
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    • pp.357-365
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    • 2014
  • A non-invasive method for ion energy distribution measurement at a RF biased surface is proposed for monitoring the property of ion bombardments in capacitively coupled plasma sources. To obtain the ion energy distribution, the measured electrode voltage is analyzed based on the circuit model which is developed with the linearized sheath capacitance on the assumption that the RF driven sheath behaves like a simple diode for a bias power whose frequency is much lower than the ion plasma frequency. The method is verified by comparing the ion energy distribution function obtained from the proposed model with the experimental result taken from the ion energy analyzer in a dual cathode capacitively coupled plasma source driven by a 100 MHz source power and a 400 kHz bias power.

Electrode Charging Effect on Ion Energy Distribution of Dual-Frequency Driven Capacitively Coupled Plasma Etcher (이중 주파수 전원의 용량성 결합 플라즈마 식각장비에서 전극하전에 의한 입사이온 에너지분포 변화연구)

  • Choi, Myung-Sun;Jang, Yunchang;Lee, Seok-Hwan;Kim, Gon-Ho
    • Journal of the Semiconductor & Display Technology
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    • v.13 no.3
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    • pp.39-43
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    • 2014
  • The effect of electrode charging on the ion energy distribution (IED) was investigated in the dual-frequency capacitively coupled plasma source which was powered of 100 MHz RF at the top electrode and 400 kHz bias on the bottom electrode. The charging property was analyzed with the distortion of the measured current and voltage waveforms. The capacitance and the resistance of electrode sheath can change the property of ion and electron charging on the electrode so it is sensitive to the plasma density which is controlled by the main power. The ion energy distribution was estimated by equivalent circuit model, being compared with the measured distribution obtained from the ion energy analyzer. Results show that the low frequency bias power changes effectively the low energy population of ion in the energy distribution.

The design and fabricationt for ion fraction measurement of plasma generator (플라즈마발생기의 이온분율 측정 장치 설계 및 제작)

  • Lee, Chan-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.368-368
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    • 2008
  • Ion implantation has been widely developed during the past decades to become a standard industrial tool. To comply with the growing needs in ion implantation, innovative technology for the control of ion beam parameters is required. Beam current, beam profile, ion fractions are of great interest when uniformity of the implant is an issue. Especially, it is important to measure the spatial distribution of beam power and also the energy distribution of accelerated ions. This energy distribution is influenced by the proportion of mass for ion in the plasma generator(ion source) and by charge exchange and dissociation within the accelerator structure and also by possible collective effects in the neutralizer which may affect the energy and divergence of ions. Hydrogen atom has been the object of a good study to investigate the energy distribution. Hydrogen ion sources typically produce multi-momentum beams consisting of atomic ion ($H^+$) and molecular ion ($H_2^+$ and $H_3^+$). In the beam injector, the molecular ions pass through a charge-exchanges gas cell and break up into atomic with one-half (from $H_2^+$) or one-third (from $H_3^+$) according to their accelerated energy. Burrell et al. have observed the Doppler shifted lines from incident $H^+$, $H_2^+$, and $H_3^+$ using a Doppler shift spectroscopy. Several authors have measured the proportion of mass for hydrogen ion and deuterium using an ion source equipped with a magnetic dipole filter. We developed an ion implanter with 50-KeV and 20-mA ion source and 100-keV accelerator tube, aiming at commercial uses. In order to measure the proportion of mass for ions, we designed a filter system which can be used to measure the ion fraction in any type of ion source. The hydrogen and helium ion species compositions are used a filter system with the two magnets configurations.

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Development and Test of ion Source with Small Orifice Cold Cathode

  • G. E. Bugrov;S. K. Kondranin;E. A. Kralkina;V. B. Pavlov;K. V. Vavilin;Lee, Heon-Ju
    • Journal of Korean Vacuum Science & Technology
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    • v.5 no.1
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    • pp.19-24
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    • 2001
  • The paper represents the results of the development and the test of "cold cathode" ion source model with 5 cm aperture where the glow discharge is utilized for generation of electrons in the cathode of the ion source. The results of probe measurements of the ion source are represented. The integral parameters such as electron energy distribution function(EEDF), electron density and mean electron energy, discharge voltage-current characteristics, and distribution of ion beam were studied.

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Measurement of Ion Energy Distribution using QMS & Ionization Enhancement by usign Magnetic Field in Triod BARE (자장을 이용한 이온화율 증대형 삼극형 BARE에서 이온화율의 증대경향과 QMS를 이용한 이온의 에너지 분포 측정)

  • 김익현;주정훈;한봉희
    • Journal of the Korean institute of surface engineering
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    • v.24 no.3
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    • pp.119-124
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    • 1991
  • Recently, the trend of research in hard coating is concentrate on developing the process of ionization rate under low operating pressure, to get the thin film with high adhesion and dense microstructures. In this study ionization rate enhancement type PVD process using permanent magnet is developed, which enhances the ionization rate by confining the plasma suppressing the wall loss of electron. By the result to investigate the characteristic of glow discharge, the ionization rate of this process is enhanced about twice as high as that of triod BARE process (about 26%), and more dense TiN microstructures are obtained in this process. Cylindrical ion energy analyzer is made and attached in front of a quadrupole mass filter for the analysis of the energy distribution of reactive gas and activated gas ions from the plasma zone. To analyze the operation mechanism of ion energy analyzer, computer simulation is performed by calculation the electric field environment using finite element method. By these analyses of ion energy distribution of outcoming ions from the plasma zone, it is found that magnetic field enhances ion kinetic energy as well as ionization rate. The other results of this study is that the foundation of feed-back system is constructed, which automatically control the partial pressure of reactive gas. In can be possible by recording the data of mass spectrum and ion energy analysis using A-D converter.

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Simulation Study of the Beam Trajectory Effect on the Magnetic Field Distribution of a Duoplasmatron

  • Park, Sae-Hoon;Lee, Sang-Hun;Kim, Yu-Seok
    • Journal of the Korean Physical Society
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    • v.73 no.8
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    • pp.1093-1098
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    • 2018
  • Recently, a gas interface system was developed for accelerator mass spectrometry with a cesium sputtering ion source. A gaseous ion source was proposed and designed to eliminate the solidification and graphitization process in radiocarbon dating. A simulation study of the ion source for a gas sample analysis system was conducted to investigate the characteristics of the ion source when different anode shapes were used, and the results are reported in this paper. The use of different anode shapes revealed the influence of magnetic field penetration on the plasma within the expansion cup. An axial magnetic field constrains the discharge, producing greater ionization density. The ion beam trajectories from the ion source were calculated using the SIMION program to examine the dependence of the changes in the magnetic field distribution on the shape of the ion source's anode.

Analysis of Time-Dependent Behavior of Plasma Sheath using Ion Fluid Model (이온유체방정식을 이용한 Plasma Sheath 시변 해석)

  • Lee, Ho-Jun;Lee, Hae-June
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.12
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    • pp.2173-2178
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    • 2007
  • Dynamics of plasma sheath was analyzed using simple ion fluid model with poison equation. Incident ion current, energy, potential distribution and space charge density profile were calculated as a function of time. The effects of initial floating sheath on the evolution of biased sheath were compared with ideal matrix sheath. The effects of finite rising time of pulse bias voltage on the ion current and energy was studied. The influence of surface charging on the evolution of sheath was also investigated

Neural Network Modeling of Ion Energy Impact on Surface Roughness of SiN Thin Films (신경망을 이용한 SiN 박막 표면거칠기에의 이온에너지 영향 모델링)

  • Kim, Byung-Whan;Lee, Joo-Kong
    • Journal of the Korean institute of surface engineering
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    • v.43 no.3
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    • pp.159-164
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    • 2010
  • Surface roughness of deposited or etched film strongly depends on ion bombardment. Relationships between ion bombardment variables and surface roughness are too complicated to model analytically. To overcome this, an empirical neural network model was constructed and applied to a deposition process of silicon nitride (SiN) films. The films were deposited by using a pulsed plasma enhanced chemical vapor deposition system in $SiH_4$-$NH_4$ plasma. Radio frequency source power and duty ratio were varied in the range of 200-800 W and 40-100%. A total of 20 experiments were conducted. A non-invasive ion energy analyzer was used to collect ion energy distribution. The diagnostic variables examined include high (or) low ion energy and high (or low) ion energy flux. Mean surface roughness was measured by using atomic force microscopy. A neural network model relating the diagnostic variables to the surface roughness was constructed and its prediction performance was optimized by using a genetic algorithm. The optimized model yielded an improved performance of about 58% over statistical regression model. The model revealed very interesting features useful for optimization of surface roughness. This includes a reduction in surface roughness either by an increase in ion energy flux at lower ion energy or by an increase in higher ion energy at lower ion energy flux.

Development of Ion Beam Monte Carlo Simulation and Analysis of Focused Ion Beam Processing (이온빔 몬테 카를로 시물레이션 프로그램 개발 및 집속 이온빔 공정 해석)

  • Kim, Heung-Bae
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.4
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    • pp.479-486
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    • 2012
  • Two of fundamental approaches that can be used to understand ion-solid interaction are Monte Carlo (MC) and Molecular Dynamic (MD) simulations. For the simplicity of simulation Monte Carlo simulation method is widely preferred. In this paper, basic consideration and algorithm of Monte Carlo simulation will be presented as well as simulation results. Sputtering caused by incident ion beam will be discussed with distribution of sputtered particles and their energy distributions. Redeposition of sputtered particles that are experienced refraction at the substrate-vacuum interface additionally presented. In addition, reflection of incident ions with reflection coefficient will be presented together with spatial and energy distributions. This Monte Carlo simulation will be useful in simulating and describing ion beam related processes such as Ion beam induced deposition/etching process, local nano-scale distribution of focused ion beam implanted ions, and ion microscope imaging process etc.

Numerical Analysis of the Incident ion Energy and Angle Distribution in the DC Magnetron Sputtering for the Variation of Gas Pressure

  • Hur, Min Young;Oh, Sehun;Kim, Ho Jun;Lee, Hae June
    • Applied Science and Convergence Technology
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    • v.27 no.1
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    • pp.19-22
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    • 2018
  • The ion energy and angle distributions (IEADs) in the DC magnetron sputtering systems are investigated for the variation of gas pressure using particle-in-cell simulation. Even for the condition of collisionless ion sheath at low pressure, it is possible to change the IEAD significantly with the change of gas pressure. The bombarding ions to the target with low energy and large incident angle are observed at low pressure when the sheath voltage drop is low. It is because the electron transport is hindered by the magnetic field at low pressure because of few collisions per electron gyromotion while the ions are not magnetized. Therefore, the space charge effect is the most dominant factor for the determination of IEADs in low-pressure magnetron sputtering discharges.